The present disclosure relates generally to turbines, and particularly to turbine rotor supports.
Current gas turbine engines utilize a bearing to support a rotor therein. The bearing is disposed within a bearing housing that is attached to an inner structure of an exhaust frame. The inner structure of the exhaust frame is located interior to an annular flow area of exhaust gases and is connected to an outer structure located exterior to the annular flow area of the gas turbine via a plurality of struts. The exhaust frame, including the inner and outer structure and struts, are made from structural steel and support the rotor and provide stiffness to the bearing housing. Each strut that projects from the inner structure to the outer structure creates an aerodynamic obstacle to a flow of exhaust, and an accompanying contribution to efficiency loss. Accordingly, an engineering compromise exists between rotor support stiffness and operational efficiency. Further, because the structural steel is not capable of withstanding turbine exhaust temperatures, cooling air is generally required. The cooling air is often provided via auxiliary blowers that are powered by the engine and therefore result in further engine efficiency losses.
Accordingly, there is a need in the art for a turbine rotor bearing support arrangement that overcomes these limitations.